NAME

       perl5i::Signature - Representing what parameters a subroutine accepts

SYNOPSIS

           func hello( $greeting, $place ) { say "$greeting, $place" }

           my $code = \&hello;
           my $signature = $code->signature;

           say $signature->num_positional_params;  # 2
           say $signature->is_method;   # false

DESCRIPTION

       A Signature is a representation of what parameters a subroutine accepts.  Each subroutine defined with
       "func" or "method" will have a signature associated with it.  You can get at it by calling the
       "signature" method on the code reference.  See "Signature Introspection" in perl5i for more details.

       Subroutines declared with Perl's built in "sub" will have no signature.

METHODS

       params

           my $params = $sig->params;

       An array ref of the parameters a subroutine takes in the order it takes them.  Currently they are just
       strings.  In the future they will be string overloaded objects.

       positional_params

           my $params = $sig->positional_params;

       Like "$sig->params" but it is just the positional parameters.

       In the future there will be named parameters.

       num_positional_params

           my $num_positional_params = $sig->num_positional_params;

       The number of named parameters the subroutine takes.

       In the future there will be named parameters.  For the purposes of determining how many arguments a
       function takes, it is most useful to look just at the positional ones.

       This is mostly an optimization for "$sig->positional_params->size".

       as_string

           my $params = $sig->as_string;

       The original signature string.

       invocant

           my $invocant = $sig->invocant;

       The invocant is the object or class a method is called on.  "invocant" will return the parameter which
       contains this, by default it is $self on a method, and nothing a regular subroutine.

       is_method

           my $is_method = $sig->is_method;

       Returns if the subroutine was declared as a method.

OVERLOADING

       Signature objects are string overloaded to return "as_string".  They are also always true to avoid
       objects taking no parameters from being confused with subroutines with no signatures.